[heap] Limit friendship of the Heap class to essentials.

src/snapshot/serialize.cc

Index: src/snapshot/serialize.cc
diff --git a/src/snapshot/serialize.cc b/src/snapshot/serialize.cc
index b1bca7bbd88b4e645ccb227fefb5ceb59e918ff9..065b0680b31712a45a1ff39fedd5fbfdcf17d58b 100644
--- a/src/snapshot/serialize.cc
+++ b/src/snapshot/serialize.cc
@@ -776,7 +776,8 @@ void Deserializer::CommitPostProcessedObjects(Isolate* isolate) {
     // Assign a new script id to avoid collision.
     script->set_id(isolate_->heap()->NextScriptId());
     // Add script to list.
-    heap->set_script_list(*WeakFixedArray::Add(factory->script_list(), script));
+    Handle<Object> list = WeakFixedArray::Add(factory->script_list(), script);
+    heap->public_set_script_list(*list);
   }
 }